Safety rotational starting appliance



F. LEDESMA May 28, 1968 SAFETY ROTATIONAL STARTING APPLIANCE Filed Oct. 4, 1966 nllllll llllhvillu INVENTOR FRANK LEDESMA ATTORNEYS United States Patent Oflice 3,385,277 Patented May 28, 1368 3 385 277 SAFETY ROTATIONAL STARTING APPLIANCE Frank Ledesma, 3552 15th St., Wyandotte, Mich. 48192 Filed Oct. 4, 1966, Ser. No. 584,126 3 Claims. (Cl. 123-185) ABSTRACT OF THE DISCLOSURE This safety rotational starting appliance for model airplane engines has an elongated casing in which is rotatably mounted a spirally-grooved engine starter shaft disposed in telescoping relationship within a tubular reciprocatory handle shaft drivingly connected thereto by an external parallel guiding connecting rod, the bent forward end of which projects through the handle shaft into the spiral groove and the rearward end of which is secured to the handle shaft. Between these ends the connecting rod is guidedly engaged by the edges of a notch in the rearward end cap of the casing to permit relative sliding while preventing relative rotation there-between. A coupling on the forward end of the starter shaft grips a hub on the engine shaft and rotates it to start the engine when a rearward pull on the handle shaft rotates the spirallygrooved starter shaft.

In the drawing, FIGURE 1 is a side elevation of a miniature internal combustion engine with a safety rotational starting appliance applied thereto and in its closed position, according to one form of the invention;

FIGURE 2 is a central longitudinal section through the safety starting appliance of FIGURE 1, also in its closed position;

FIGURE 3 is a cross-section taken along the line 33 in FIGURE 2;

FIGURE 4 is a side elevation of the propeller spinner of the engine which is engaged by the starting device of the present invention;

FIGURE 5 is a right-hand end elevation of the propeller spinner shown in FIGURE 4; and

FIGURE 6 is a cross-section taken along the line 6-6 in FIGURE 1.

Referring to the drawings in detail, FIGURE 1 shows a miniature internal combustion engine of conventional design, such as is used for the propulsion of model aircraft, and available commercially upon the open market in a variety of styles. All, however, have the usual crankcase 12 and cylinder 14 containing a piston which drives a crankshaft (not shown) to which an aircraft propeller 16 is operatively connected. Secured to the hub 15 of the propeller 16 and thereby operatively connected to the crankshaft is a tapered propeller spinner 18 (FIGURE 4) consisting of an ogival body 20 upon which are longitudinally-extending and radially projecting converging ribs 22.

The safety starting appliance, generally designated 30, of the present invention is housed in an elongated tubular casing 32 consisting of a tubular barrel 34 (FIGURE 2) closed at its forward and rearward ends by an aperture-d closure disc 36 and a flanged apertured cap 38 respectively. The closure disc 36 is welded or otherwise secured at 40 to the forward end of the tubular barrel 34, whereas the closure cap 38 is removably secured to the rearward end thereof in any suitable manner, as by threading.

Rotatably mounted in the casing 32 is a spirallygrooved starter shaft 42, the forward end 44 of which is tightly secured in a socket 46 within a soft resilient coupling collar 48 of rubber or other suitable resilient material having in its forward end an ogival tapered recess 50 configured to fit the propeller spinner 18. The starter shaft 42 on opposite sides of the forward closure disc 36 is spacedly grooved to receive a pair of spaced C- washers 52 and 54.

The spirally-grooved starter shaft 42, as its name signifies, is provided with a spiral or helical groove 56 extending from a location near the C-washers 52 and 54 two revolutions to the rearward end thereof. The spiral groove 56 is engaged by the radially-bent forward end 58 of a guiding connecting rod 60 which extends through a hole 62 in the forward portion of a hollow tubular handle shaft 64, the rearward end portion of which, adjacent the cap 38, is provided with a hole 66 through which the Z-shaped bent end 68 of the connecting rod 60 is hooked and thereby secured. Between its opposite ends 58 and 69, the rod 60 extends parallel to the handle shaft 64. The cap 38, adjacent the bent portion 68 (FIGURE 3) is notched out as at 70 to slidably receive and pass the connecting rod 60, which for most of its length passes outside the tubular handle shaft 64 but inside the barrel 34, but which at the same time prevents relative rotation between the casing 32 and the handle shaft 64.

The forward end of the tubular handle shaft 64, in the closed position of the starting device 30, engages the rearward C-washer 54 and rearwardly thereof is provided with an annular enlargement or abutment 72 which may consist of a washer, welded or otherwise secured thereto. The enlargement 72 serves as an abutment for a stop bushing 74 which encircles the tubular handle shaft 64 and also the connecting rod 60 so that its axis is eccentric to the axes of the handle shaft 64 and spirallygrooved starter shaft 42. Mounted on the rearward end of the tubular handle shaft 64 is a centrally-bored handle 76, both of which are drilled diametrically to receive an anchoring pin 78. The barrel 34 near its forward end is provided with an oil hole for lubrication purposes.

In the operation of the invention, to start the internal combustion engine 12, the operator, with the safety starting device 30 in its closed position of FIGURES 1 and 2, pushes the resilient coupling collar firmly onto the propeller spinner 18 attached to the hub 15 of the aircraft propeller 16 so that the ribs 22 engage and indent the rubber or other elastic deformable material of the coupling collar 43 so as to establish a driving connection therebetween, as shown in FIGURE 6. Holding the housing 30 stationary in one hand, the operator grasps the handle 76 in his other hand and pulls sharply upon it in a rearward direction, thereby moving rearwardly the tubular handle shaft 64 and the connecting rod 60. This action causes the hooked forward end 58 of the connecting rod 61) to forcibly engage the spiral groove 56 and forcibly rotate the spirally-grooved starter shaft 42, the coupling collar 48, the spinner 18, the propeller hub 15 and the engine crankshaft (not shown) starting the internal combustion engine 10. The handle shaft 64 may be withdrawn until the rearward end of the stop bushing 74 engages the end wall of the end cap 38 after imparting approximately two revolutions to the spirally-grooved shaft 42.

The same rearward pull which starts the engine 10, however, also pulls the starting device 30 rearwardly away from the spinner 18, thereby disengaging the resilient coupling collar 48 therefrom. In this way, injury to the operator is prevented and for the further reason that his hands are always spaced away from the aircraft propeller 16 which, upon the starting of the engine 10. rotates rapidly. If, however, the operator should neglect to pull the device 30 away in time, the resilience of the coupling collar 48, upon starting of the engine 10, permits the tapered ribs 22 of the nose 18 to disengage themselves from driving engagement with the side wall of the tapered recess 50 and consequently to safely interrupt the driving connection as soon as the engine starts.

What I claim is:

1. A safety rotational starting appliance for a miniature internal combustion engine having an output shaft, said appliance comprising:

a spinner member adapted to be operatively connected to the engine output shaft,

a coupling member having a recess therein receiving said spinner member in releasable driving engagement therewith,

an elongated hollow casing,

a spirally-grooved starter shaft rotationally mounted in said casing and drivingly connected to said coupling member,

means disposed between said starter shaft and said casing for restraining said starter shaft against axial movement,

a tubular handle shaft reciprocably mounted in said casing in telescoping relationship about said starter shaft and having secured thereto an elongated connecting rod extending along the outside of said tubular handle shaft and having a bent end extending through said handle shaft into driving engagement with the spiral groove of said starter shaft, said handle shaft having a handle mounted thereon near its rearward end,

and means disposed between said handle shaft and said casing and engaging said connecting rod for restraining said handle shaft against rotation relatively to said casing while permitting relative sliding motion therebetween.

2. A safety rotational starting appliance, according to claim 1 wherein said rod has its rearward end secured to the rearward portion of said handle shaft.

3. A safety rotational starting appliance according to claim 1, wherein said casing near its rearward end has a closure member thereon with an opening therein for the passage of said handle shaft and also has adjacent said opening an aperture with its edge engaging said connecting rod and constituting said rotation-restraining means.

References Cited UNITED STATES PATENTS 1,178,989 4/1916 Branson 746 2,625,143 l/1953 Demitz l23-l79 FOREIGN PATENTS 725,527 3/ 1955 Great Britain.

WENDELL E. BURNS, Primary Examiner. 

